[keycloak-dev] Custom federation - webservice

I'm developing a custom federation that communicates with my user repository via webservices. Probably this is a very strange scenario for a federation but that's the unique way that I have to communicate with the repository. My problem is that, as the webservices only exposes methods such as createUser and updateUser, I'm having problems with registrations and user profile updates because I'm not being able to do atomic calls to the webservice methods, with all the information that I need. As far as I know, from the properties file example and from the ldap federation source (probably I'm missing something) it seems that the federation api is intended to update and sync attribute by attribute (Keycloak <-> Federation). Am i wrong? Do you suggest another approach? Should I give up from having a federation that uses a webservice? Thank you.